uitsus 293 



concave, with inner, middle and outer ridges, the inner and middle 

 low and confluent in i v Canines large and strong, oval or 

 slightly ovate in cross section, the longest diameter at level of 

 alveolus equal to or slightly greater than distance from alveolus 

 to median line of palate ; lower canine shorter and a little more 

 curved than upper ; a slightly developed posterior and antero- 

 internal longitudinal ridge, most evident in upper tooth ; no 

 cingulum. First and third upper premolars small, flat topped, 

 with slightly indicated cusp and posterior and antero-internal 

 ridge, the crown area slightly less than that of smallest incisor, 

 the first close to canine, the third close to large premolar ; third 

 near middle of space between first and second, much smaller than 

 the others and frequently deciduous, its crown indefinitely 

 rounded ; fourth upper premolar with crown area about half that 

 of first molar, its general outline triangular with apex directed 

 forward, the outer side longest, the posterior border shortest, the 

 contrast between them sometimes noticeable, in other instances 

 slight, the three cusps lying near respective angles, the anterior 

 highest (reaching level of main cusps of molars) and most robust, 

 the posterointernal and postero-external abruptly smaller, sub- 

 equal, the inner usually lower than the outer ; a small accessory 

 tubercle usually present at posterior base of postero-outer cusp ; 

 cingulum obsolete but usually visible along inner base of anterior 

 cusp and outer base of postero-external cusp ; first and second 

 lower premolars approximately like corresponding upper teeth in 

 both size, form and position ; third very early deciduous, usually 

 if not always absent in adult individuals ; fourth in contact with 

 first molar and with from one-third to nearly one-half its crown 

 area, the outline irregularly quadrilateral with well developed 

 antero-external cusp nearly as high as main cusps of molars, a 

 rudimentary antero-internal cingulum cusp, and a tuberculated 

 ridge extending along outer side of crown from antero-external 

 cusp to posterior border ; occasionally a similar ridge is present 

 on inner side of crown, its anterior tubercle forming an evident 

 cusp at inner posterior base of main cusp. First upper molar 

 with crown much less than twice as long as broad, its outer side 

 bi-convex, its inner side evenly rounded, its two outer cusps 

 sub-equal in both height and diameter, the two inner cusps 

 decidedly lower than outer, and less well defined, owing to the 

 presence of a low, ridge-like tubercle between them ; both outer 

 and inner cusps when unworn have distinct though low anterior 

 and posterior trenchant ridge ; space between outer and inner 

 cusps occupied by a rather well defined longitudinal groove, the 

 surface of which is marked by irregular low ridges and furrows ; 

 cingulum obsolete, but indicated in the regions between the 

 cusps ; second upper molar nearly twice as long as broad, the 

 anterior two-thirds approximately like first molar, with the same 

 four cusps and intermediate longitudinal groove, the main axis 

 of which is, however, in axis of tooth-row instead of slightly 



